The present invention relates to a sealing device for a rotary regenerative heat exchanger, and more particularly to a sealing device for a rotary regenerative heat exchanger including a heat exchanger housing, a rotary regenerator accommodated in the housing, a slide member slidably contacting with one side surface of the rotary regenerator, and a thin flat seal plate, one end of which engages with the other side surface of the slide member and the other end of which is secured with housing of the heat exchanger.
A conventional rotary regenerative heat exchanger for regenerating gas turbine engine is shown in FIGS. 1 and 2, which includes a compressor 1, a compressor turbine 2, and a power turbine 5.
A working fluid passage 3 between the compressor 1 and the compressor turbine 2 is inserted with a burner 4. The passage 3 upstream of the burner 4 is formed adjacent with an exhaust passage 6 of the power turbine 5, in a housing 7 of a rotary regenerative heat exchanger. A rotary regenerator 8 communicates with both passages 3 and 6 and is rotatably mounted in the housing 7. A sealing device 9 is mounted around the exhaust passage 6 of the power turbine 5, as shown in FIG. 2. A pressure chamber 10 is formed around the rotary regenerator 8 and communicates with the passage 3. Pressure in the pressure chamber 10 is utilized to urge the sealing device 9 and prevent leakage across the sealing device 9.
Conventional construction of such a sealing device 9 is shown in FIG. 3. One side surface of a sliding member 11 consisting essentially of carbon is slidably engaged with side surface of the rotary regenerator 8. A holder 12 holds the other surface of the sliding member 11 while the opposite surface 12a of the holder 12 is secured with smaller end of conical seal plate 13. Larger end of the seal plate 13 is engaged with a seal surface 7a of the housing 7. A supporting member 14 is laid on the housing side surface of the seal plate 13, and is secured to the holder 12. Pressure difference between the pressure chamber 10 and the exhaust passage 6 elastically deforms and urges the seal plate 13 on the seal surface 7a of the housing 7. The supporting member 14 is to support the seal plate 13 from excessive deformation.
Other conventional sealing device of the rotary regenerative heat exchanger is shown in FIG. 4. Same reference numeral designates corresponding part or portion shown in FIG. 3. The seal plate 13 shown in FIG. 4 is tapered in opposite direction to that shown in FIG. 3. The seal plate 13 and the support 14 are secured to the housing 7, while the outer end of the seal plate 13 is urged against the surface 12a of the holder 12.
In the conventional sealing devices shown in FIGS. 1 to 4, when the sliding member 11 or the main housing side sliding member 15 is worn, distance between the seat surface 12a of the holder 12 which holds the seal plate 13 and the seal surface 7a of the housing 7 increases gradually. To adapt for the change of the distance and to maintain the desired sealing property, deformation of the seal plate 13 must be increased. Thus, for example, a plurality of slits 16 are formed through the peripheral portion of the seal plate 13 as shown in FIG. 5. Such slits tend to invite gas leakage which is another disadvantage. When the number of the slits are decreased, cracks 17 shown in FIG. 5 may be formed by the deformation stress applied to the seal plate 13 so that the desired sealing property may be impaired.
To mitigate such disadvantages, another known sealing device shown in FIG. 6 utilizes flat seal plate 13 and flat supporting member 14 laid on the seal plate 13, which are secured to the housing 7 to eliminate the slits 16 shown in FIG. 5. As the supporting member 14 limits deformation of the seal plate 13, follow-up performance of the seal plate 13 is impaired. Thus, when the sliding members 11 and 15 are worn, sealing property between the seat surface 12a of the holder 12 and the outer edge of the seal plate is impaired to form a clearance therebetween. Consequently, starting performance of the gas turbine engine is impaired due to the leakage of gas through the clearance.